Nonsurgical Management of Single-Sided Deafness: Contralateral Routing of Signal

Hearing Benefits of Cochlear Implantation in Older Adults With Asymmetric Hearing Loss

OBJECTIVE

To examine the benefit of cochlear implantation (CI) in older adults with single-sided deafness (SSD) and asymmetric hearing loss (AHL).

STUDY DESIGN

Retrospective chart review.

SETTING

Veterans Affairs Medical Center and tertiary referral center, 2019-2023.

PATIENTS

Adults ≥60 years with either SSD or AHL who underwent unilateral CI.

INTERVENTIONS

Cochlear implantation.

MAIN OUTCOME MEASURES

Audiometric testing (preoperative and postoperative pure-tone averages [PTA], sentence and word recognition), presence of hearing-related symptoms, CI utilization.

RESULTS

Twelve subjects were identified who underwent CI for SSD or AHL after being determined to obtain limited benefit from an appropriately fitted unilateral hearing aid (mean age 72.6 yr, 91.7% male, 100% White). Mean duration of hearing loss was 13.7 years, and the most common etiology was idiopathic (25%). Subjects were followed for a median length of 9.1 months after implantation. Mean daily CI use was 9.3 hours per day.Preoperatively, median unaided PTAs of the implanted and contralateral ear were 103.1 and 41.3 dB, respectively; median aided AZBio sentence recognition values in quiet were 0.0 and 81.5%, respectively. In the implanted ear with the CI in use, median PTA improved from 103.1 to 28.1 dB ( p = 0.002), CNC word scores improved from 0.0 to 42.0% ( p = 0.027), CNC phoneme scores improved from 0.0 to 60.0% ( p = 0.043), and AZBio improved from 0.0 to 48.0% ( p = 0.012). Seventy-five percent preoperatively, compared to 33.3% postoperatively, experienced dizziness ( p = 0.063), whereas 83.3 and 33.3% experienced tinnitus ( p = 0.375).

CONCLUSIONS

In this group of older adults with SSD or AHL, CI demonstrated significant benefits in hearing thresholds and speech recognition in the implanted ear. Moreover, the average of 9.3 hours of daily use suggests that patients' CI is tolerated and beneficial in this population.

Brazilian Society of Otology task force - single sided deafness - recommendations based on strength of evidence

OBJECTIVE

To make evidence-based recommendations for the treatment of Single-Sided Deafness (SSD) in children and adults.

METHODS

Task force members were instructed on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on SSD were eligible for inclusion. The American College of Physicians' guideline grading system and the American Thyroid Association's guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.

RESULTS

The topics were divided into 3 parts: (1) Impact of SSD in children; (2) Impact of SSD in adults; and (3) SSD in patients with temporal bone tumors.

CONCLUSIONS

Decision-making for patients with SSD is complex and multifactorial. The lack of consensus on the quality of outcomes and on which measurement tools to use hinders a proper comparison of different treatment options. Contralateral routing of signal hearing aids and bone conduction devices can alleviate the head shadow effect and improve sound awareness and signal-to-noise ratio in the affected ear. However, they cannot restore binaural hearing. Cochlear implants can restore binaural hearing, producing significant improvements in speech perception, spatial localization of sound, tinnitus control, and overall quality of life. However, cochlear implantation is not recommended in cases of cochlear nerve deficiency, a relatively common cause of congenital SSD.

Directionality in BiCROS hearing aids: an investigation of objective and subjective outcomes

OBJECTIVES

To assess the effect of forward and omnidirectional microphone configurations in BiCROS versus monaural hearing aids on objective and subjective outcomes in different noise conditions.

DESIGN

After fitting and a 4-week acclimatisation period, speech recognition and sound quality were measured using forward directional, omnidirectional, and unaided settings. Two noise configurations were used, surrounding noise and noise presented from the aided (better) ear. Subjective outcomes were assessed using the SSQ-b and BBSS questionnaires and participant interviews.

STUDY SAMPLE

Eighteen adult participants (mean: 74.6 y; range: 61-94 y; ten males, eight females) with mild to moderately severe SNHL in their better ear (PTA0.5-4khz > 20 dB HL) and limited usable hearing in their poorer ear (average PTA0.5-4khz > 100 dB HL).

RESULTS

Significant improvement in speech recognition and sound quality for BiCROS and monaural directional settings over omnidirectional and unaided, in both noise configurations. There were no significant differences observed between monoaural and BiCROS directional settings.

CONCLUSION

Speech in noise recognition and sound quality scores demonstrated a significant directional benefit for both BiCROS and monaural directional fitting settings over omnidirectional and unaided conditions. Unique BiCROS-specific experiences were identified in a patient-oriented approach. These can inform the development of BiCROS-tailored tools.

Prevalence of Single-Sided Deafness in a Tertiary Healthcare Hospital in Mumbai

PURPOSE

The current study was taken up to estimate the prevalence of Single Sided Deafness (SSD) in a tertiary healthcare hospital in Mumbai. Also to determine the acceptance of Contralateral routing of offside signal (CROS) devices by individuals with SSD.

METHOD

A retrospective study design was followed to collect data from September 2020 to September 2022. The data were collected by reviewing the files of the cases diagnosed with Single-Sided Deafness in a tertiary health care hospital in Mumbai.

RESULT

The prevalence of SSD was found to be 24% for the given period. It was observed that 50 out of 4456 took a free trial and 2 bought the device.

CONCLUSION

The poor acceptance and purchase of CROS are attributed to the cost, and missed benefits of true binaural hearing in localization and hearing in noise. These benefits can be achieved by using CI, however, the cost and fear of surgery refrained the participants. Also, participants were observed to learn great use of communication repair strategies. Therefore, it is required to counsel individuals with SSD for CI and provide knowledge about care for the better with regular audiological follow-up.

Single-Sided Deafness and Hearing Rehabilitation Modalities: Contralateral Routing of Signal Devices, Bone Conduction Devices, and Cochlear Implants

Single sided deafness (SSD) is characterized by significant sensorineural hearing loss, severe or profound, in only one ear. SSD adversely affects various aspects of auditory perception, including causing impairment in sound localization, difficulties with speech comprehension in noisy environments, and decreased spatial awareness, resulting in a significant decline in overall quality of life (QoL). Several treatment options are available for SSD, including cochlear implants (CI), contralateral routing of signal (CROS), and bone conduction devices (BCD). The lack of consensus on outcome domains and measurement tools complicates treatment comparisons and decision-making. This narrative overview aims to summarize the treatment options available for SSD in adult and pediatric populations, discussing their respective advantages and disadvantages. Rerouting devices (CROS and BCD) attenuate the effects of head shadow and improve sound awareness and signal-to-noise ratio in the affected ear; however, they cannot restore binaural hearing. CROS devices, being non-implantable, are the least invasive option. Cochlear implantation is the only strategy that can restore binaural hearing, delivering significant improvements in speech perception, spatial localization, tinnitus control, and overall QoL. Comprehensive preoperative counseling, including a discussion of alternative technologies, implications of no treatment, expectations, and auditory training, is critical to optimizing therapeutic outcomes.

Sound Localization in Single-Sided Deafness; Outcomes of a Randomized Controlled Trial on the Comparison Between Cochlear Implantation, Bone Conduction Devices, and Contralateral Routing of Signals Hearing Aids

There is currently a lack of prospective studies comparing multiple treatment options for single-sided deafness (SSD) in terms of long-term sound localization outcomes. This randomized controlled trial (RCT) aims to compare the objective and subjective sound localization abilities of SSD patients treated with a cochlear implant (CI), a bone conduction device (BCD), a contralateral routing of signals (CROS) hearing aid, or no treatment after two years of follow-up. About 120 eligible patients were randomized to cochlear implantation or to a trial period with first a BCD on a headband, then a CROS (or vice versa). After the trial periods, participants opted for a surgically implanted BCD, a CROS, or no treatment. Sound localization accuracy (in three configurations, calculated as percentage correct and root-mean squared error in degrees) and subjective spatial hearing (subscale of the Speech, Spatial and Qualities of hearing (SSQ) questionnaire) were assessed at baseline and after 24 months of follow-up. At the start of follow-up, 28 participants were implanted with a CI, 25 with a BCD, 34 chose a CROS, and 26 opted for no treatment. Participants in the CI group showed better sound localization accuracy and subjective spatial hearing compared to participants in the BCD, CROS, and no-treatment groups at 24 months. Participants in the CI and CROS groups showed improved subjective spatial hearing at 24 months compared to baseline. To conclude, CI outperformed the BCD, CROS, and no-treatment groups in terms of sound localization accuracy and subjective spatial hearing in SSD patients. TRIAL REGISTRATION Netherlands Trial Register (https://onderzoekmetmensen.nl): NL4457, CINGLE trial.

Hearing Aid in Vestibular-Schwannoma-Related Hearing Loss: A Review

(1) Background: Several types of hearing aids are available for the rehabilitation of vestibular-schwannoma (VS)-related hearing loss. There is a lack of recently published papers regarding this theme. The aim of the present work is to organize current knowledge. (2) Methods: A review of the literature regarding the topics "vestibular schwannoma", "hearing loss", and "hearing aid" was performed. Nineteen studies were thus considered. (3) Results: Conventional hearing aids, contralateral routing of signal (CROS) aids, bone anchored hearing aids (BAHA), and others are available options for hearing rehabilitation in VS patients. The speech discrimination score (SDS) is considered the best measure to assess candidacy for rehabilitation with hearing aids. The best hearing rehabilitative conditions in VS patients when using conventional hearing aid devices are a mild-moderate hearing loss degree with good word recognition (more than 50% SDS). CROS-Aid and BAHA are reported to be beneficial. CROS-Aid expands on the area of receiving hearing. BAHA aids use direct bone-conduction stimulation. Unfortunately, there are no available studies focused specifically on VS patients that compare CROS and BAHA technologies. (4) Conclusions: Hearing aids, CROS, and BAHA are viable options for rehabilitating hearing impairment in VS, but require an accurate case-by-case audiological evaluation for rehabilitating hearing impairment in VS. Further studies are needed to prove if what is currently known about similar hearing illnesses can be confirmed, particularly in the case of VS.

Contralateral Routing of Signal Disrupts Monaural Sound Localization

OBJECTIVES

In the absence of binaural hearing, individuals with single-sided deafness can adapt to use monaural level and spectral cues to improve their spatial hearing abilities. Contralateral routing of signal is the most common form of rehabilitation for individuals with single-sided deafness. However, little is known about how these devices affect monaural localization cues, which single-sided deafness listeners may become reliant on. This study aimed to investigate the effects of contralateral routing of signal hearing aids on localization performance in azimuth and elevation under monaural listening conditions.

DESIGN

Localization was assessed in 10 normal hearing adults under three listening conditions: (1) normal hearing (NH), (2) unilateral plug (NH-plug), and (3) unilateral plug and CROS aided (NH-plug + CROS). Monaural hearing simulation was achieved by plugging the ear with E-A-Rsoft™ FX™ foam earplugs. Stimuli consisted of 150 ms high-pass noise bursts (3-20 kHz), presented in a random order from fifty locations spanning ±70° in the horizontal and ±30° in the vertical plane at 45, 55, and 65 dBA.

RESULTS

In the unilateral plugged listening condition, participants demonstrated good localization in elevation and a response bias in azimuth for signals directed at the open ear. A significant decrease in performance in elevation occurs with the contralateral routing of signal hearing device on, evidenced by significant reductions in response gain and low r2 value. Additionally, performance in azimuth is further reduced for contralateral routing of signal aided localization compared to the simulated unilateral hearing loss condition. Use of the contralateral routing of signal device also results in a reduction in promptness of the listener response and an increase in response variability.

CONCLUSIONS

Results suggest contralateral routing of signal hearing aids disrupt monaural spectral and level cues, which leads to detriments in localization performance in both the horizontal and vertical dimensions. Increased reaction time and increasing variability in responses suggests localization is more effortful when wearing the contralateral rerouting of signal device.

Etiology, Severity, Audiogram Type, and Device Usage in Patients with Unilateral Moderate to Profound Sensorineural Hearing Loss in Japan

BACKGROUND

Few studies have reported on the etiology, severity, or device usage of unilateral sensorineural hearing loss (UHL) compared to bilateral hearing loss. Therefore, this study investigated the characteristics of UHL in adults and children.

METHODS

We performed a survey using questionnaires for secondary and tertiary otolaryngology institutions.

RESULTS

We included 15,981 patients (1549 children and 14,432 adults) from 196 institutions with otolaryngology residency programs and 2844 patients (336 children and 2508 adults) from 27 institutions with board members of the Japan Audiology Society. The latter submitted audiological data. Among children, most diagnoses were made at age 0. Approximately half of them had profound hearing loss, and 37 children (2.2%) used hearing devices. Among adults, the number of cases increased with age, but decreased when people reached their 80s and 90s. More than half of them had moderate hearing loss. Sudden sensorineural hearing loss was the most common cause of UHL of all ages; 4.4% of UHL patients used hearing devices, and most of the device users (98.6%) selected a conventional hearing aid.

CONCLUSIONS

Hearing aid use is limited in children and adults with UHL in Japan. There could be many candidates with UHL for intervention such as a cochlear implant.

Hearing Rehabilitation in Vestibular Schwannoma

The most common complaint among patients with vestibular schwannoma (VS) is hearing loss. This significantly affects the quality of life before, during, and after treatment for patients with VS. Untreated hearing loss in VS patients may even lead to depression and feelings of social isolation. A variety of devices are available for hearing rehabilitation for patients with vestibular schwannoma. These include contralateral routing of hearing signals (CROSs), bone-anchored hearing devices, auditory brainstem implants (ABI), and cochlear implants. In the United States, ABI is approved for patients 12 years of age and older with neurofibromatosis type 2. In the past few years, cochlear implantation has been offered simultaneously or sequentially with tumor resection or irradiation, or even to patients whose VS have been monitored with serial imaging. However, determining the functional integrity of the auditory nerve in patients with vestibular schwannoma is a challenge. This review article consists of (1) the pathophysiology of vestibular schwannoma (VS), (2) hearing loss in VS, (3) treatment of VS and associated hearing loss, (4) options for auditory rehabilitation in patients with VS with their individual benefits and limitations, and (5) challenges in hearing rehabilitation in this cohort of patients to determine auditory nerve functionality. (6) Future directions.

Speech Perception in Noise and Sound Localization for Cochlear Implant With Single-Sided Deafness Compared With Contralateral Routing of Signal Hearing Aids

OBJECTIVE

Cochlear implantation (CI) for the treatment of single-sided deafness (SSD) is a relatively new treatment modality. Although comparing the effectiveness of CI and contralateral routing of signal (CROS) hearing aids (HAs) is important, very few reports on this topic exist. In this study, objective assessments and subjective assessments were conducted to determine which SSD individuals would prefer CI or CROS HAs.

MATERIALS AND METHODS

Objective assessments (speech perception and sound localization) and subjective assessments (Hearing Handicap Inventory for Adults (HHIA), Abbreviated Profile of Hearing Aid Benefit (APHAB), MOS Short-Form 36-Item Health Survey version 2 (SF-36v2)) were performed on 87 SSD patients. Of the 87 SSD patients, 33 patients hoped for CROS HAs, and 17 patients hoped for CI. The CI group underwent subjective and objective assessments at 6 and 12 months postoperatively. The CROS HAs group underwent objective assessments at 1 month after wearing CROS HAs.

RESULTS

After the intervention, the localization ability was significantly improved in the CI group (p < 0.05) with no significant improvement in that of the CROS HAs group (p = 0.48). No significant improvement in speech perception in noise was observed in the CROS (Signal-to-Noise ratio + 10, p = 0.08; SN + 0, p = 0.17); however, a significant improvement in the CI group was observed at 12 months postoperatively. The APHAB subscale "background noise" and SF-36v2 health concepts of role-physical, general health, vitality, role-emotional, and mental health were significantly higher in the CI group.

CONCLUSION

CI was superior to CROS HAs in speech perception in terms of noise and sound localization. Patients with postlingual acute-onset hearing loss and more handicaps and a more positive view of their hearing loss possibly tend to choose CI.

Single-Sided Deafness: Emotional and Social Handicap, Impact on Health Status and Quality of Life, Functional Hearing, and the Effects of Cochlear Implantation

OBJECTIVE

To evaluate the functional and subjective outcomes in individuals with single-sided deafness (SSD) treated with a cochlear implant (CI).

METHODS

Eighty-one adult CI users with SSD participated in this study. Functional assessments consisted of speech in noise testing and localization. Subjective assessments consisted of the Speech Spatial Quality of Hearing Scale, the Tinnitus Reaction Questionnaire, the Abbreviated Profile of Hearing Aid Benefit questionnaire, the Hearing Handicap Inventory for Adults questionnaire, and the Glasgow Health Status Inventory and the Glasgow Benefit Inventory questionnaires.

RESULTS

SSD has remarkable consequences on quality of life (QoL) and imposes a substantial emotional and social handicap on the individuals. Self-reported QoL improved after CI with tinnitus intrusion significantly reduced as early as 3 months post-CI. A significant improvement was seen in all speech understanding in noise configurations. Localization ability significantly improved with CI on.

CONCLUSION

Our findings demonstrate that SSD reduces social and psychological QoL and imposes a remarkable level of handicap as per general and specific self-assessments tool. CI provided a significant improvement in function including speech understanding in noise and localization ability, as well as improved QoL and reduced tinnitus significantly in both the early and long terms.

The Core Rehabilitation Outcome Set for Single-Sided Deafness (CROSSSD) study: International consensus on outcome measures for trials of interventions for adults with single-sided deafness

Background

Single-sided deafness (SSD) has functional, psychological, and social consequences. Interventions for adults with SSD include hearing aids and auditory implants. Benefits and harms (outcome domains) of these interventions are until now reported inconsistently in clinical trials. Inconsistency in reporting outcome measures prevents meaningful comparisons or syntheses of trial results. The Core Rehabilitation Outcome Set for Single-Sided Deafness (CROSSSD) international initiative used structured communication techniques to achieve consensus among healthcare users and professionals working in the field of SSD. The novel contribution is a set of core outcome domains that experts agree are critically important to assess in all clinical trials of SSD interventions.

Methods

A long list of candidate outcome domains compiled from a systematic review and published qualitative data, informed the content of a two-round online Delphi survey. Overall, 308 participants from 29 countries were enrolled. Of those, 233 participants completed both rounds of the survey and scored each outcome domain on a 9-point scale. The set of core outcome domains was finalised via a web-based consensus meeting with 12 participants. Votes involved all stakeholder groups, with an approximate 2:1 ratio of professionals to healthcare users participating in the Delphi survey, and a 1:1 ratio participating in the consensus meeting.

Results

The first round of the survey listed 44 potential outcome domains, organised thematically. A further five outcome domains were included in Round 2 based on participant feedback. The structured voting at round 2 identified 17 candidate outcome domains which were voted on at the consensus meeting. Consensus was reached for a core outcome domain set including three outcome domains: spatial orientation, group conversations in noisy social situations, and impact on social situations. Seventy-seven percent of the remaining Delphi participants agreed with this core outcome domain set.

Conclusions

Adoption of the internationally agreed core outcome domain set would promote consistent assessment and reporting of outcomes that are meaningful and important to all relevant stakeholders. This consistency will in turn enable comparison of outcomes reported across clinical trials comparing SSD interventions in adults and reduce research waste. Further research will determine how those outcome domains should best be measured.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06702-1.

American Cochlear Implant Alliance Task Force Guidelines for Clinical Assessment and Management of Adult Cochlear Implantation for Single-Sided Deafness

The indications for cochlear implantation have expanded to include individuals with profound sensorineural hearing loss in the impaired ear and normal hearing (NH) in the contralateral ear, known as single-sided deafness (SSD). There are additional considerations for the clinical assessment and management of adult cochlear implant candidates and recipients with SSD as compared to conventional cochlear implant candidates with bilateral moderate to profound sensorineural hearing loss. The present report reviews the current evidence relevant to the assessment and management of adults with SSD. A systematic review was also conducted on published studies that investigated outcomes of cochlear implant use on measures of speech recognition in quiet and noise, sound source localization, tinnitus perception, and quality of life for this patient population. Expert consensus and systematic review of the current literature were combined to provide guidance for the clinical assessment and management of adults with SSD.

Objective Comparison of Benefits Derived From Contralateral Routing of Signal Hearing Aid and Bone Conduction Device in Noisy Surroundings in Patients With Single-Sided Deafness

Background and Objectives

Single-sided deafness (SSD) leads to non-participation of the diseased ear in generating adequate auditory input, which results in poor speech discrimination in noisy surroundings. The present study objectively compared the audiological benefits rendered by contralateral routing of signal (CROS) hearing aid and bone conduction device (BCD) in patients with SSD >70 dB HL using the modified hearing in noise test (HINT).

Materials and Methods

Patients with SSD >70 dB HL in poor and clinically normal hearing in the better ear were enrolled. Patients aged <18 or >70 years, with a history of neurological insult or ear infection in the last 3 months, mental retardation, psychiatric or developmental disorders, and diabetes were excluded. Modified HINT was performed with the affected ear unaided, aided with CROS hearing aid, and with BCD, generating three groups. Noise signal was presented at a fixed intensity of 65 dB at the neutral position in the center and speech signal was presented to either ear sequentially. The test was repeated with the speech signal fixed at the neutral position and the noise signal presented to either ear.

Results

BCD led to a better signal-to-noise ratio (SNR) than CROS hearing aid in all situations except when noise was centralized and speech was presented to the affected ear.

Conclusions

A benefit was observed when auditory rehabilitation was used for the affected ear as demonstrated by better SNR scores. The results showed that BCD performed better than CROS hearing aid.

Can the use of the CROS system provide head shadow effect contribution to unilateral Cochlear Implant Users?

PURPOSE

The aim of this study was to evaluate the contribution of the CROS system on the head shadow effect in unilateral implant users.

METHODS

Prospective cross-sectional study, approved by the ethics committee under protocol 2.128.869. Eleven adults with post-lingual deafness users of unilateral Advanced Bionics CI were selected. Speech recognition was evaluated with recorded words presented at 65dBA at 0o azimuth and at 90o on the side contralateral to the CI, with noise at 55dBA, using CI alone and CI + CROS system. The results were analyzed using paired t-test with a 0.05 alpha.

RESULTS

The mean speech recognition scores were significantly better with CI + CROS in relation to the condition of CI alone (p <0.05, p <0.005 and p <0.005 respectively). In the presentation at 0o azimuth, no significant differences were found.

CONCLUSION

Users of unilateral CI without useful residual hearing for the use of hearing aids or unable to undergo bilateral surgery can benefit from the CROS device for speech recognition, especially when the speech is presented on the side contralateral to the CI.

Hearables as a gateway to hearing health care: A review

The market for hearing technology is evolving—with the emergence of hearables, it now extends beyond hearing aids and includes any ear-level devices with wireless connectivity (i.e., wireless earbuds). However, will this evolving marketplace bring forth opportunities or challenges to individuals’ hearing health care and the profession of audiology and otolaryngology? The debate has been ongoing. This study explores the wide spectrum of hearables available in the market and discusses the necessity of high-quality clinical evidence prior to the implementation of over-the-counter devices into clinical practice.

Short-term outcomes of cochlear implantation for single-sided deafness compared to bone conduction devices and contralateral routing of sound hearing aids-Results of a Randomised controlled trial (CINGLE-trial)

Single-sided deafness (SSD) leads to difficulties with speech perception in noise, sound localisation, and sometimes tinnitus. Current treatments (Contralateral Routing of Sound hearing aids (CROS) and Bone Conduction Devices (BCD)) do not sufficiently overcome these problems. Cochlear implants (CIs) may help. Our aim was to evaluate these treatments in a Randomised Controlled Trial (RCT). Adult SSD patients were randomised using a web-based randomisation tool into one of three groups: CI; trial period of 'first BCD, then CROS'; trial period of 'first CROS, then BCD'. After these trial periods, patients opted for BCD, CROS, or No treatment. The primary outcome was speech perception in noise (directed from the front (S0N0)). Secondary outcomes were speech perception in noise with speech directed to the poor ear and noise to the better ear (SpeNbe) and vice versa (SbeNpe), sound localisation, tinnitus burden, and disease-specific quality of life (QoL). We described results at baseline (unaided situation) and 3 and 6 months after device activation. 120 patients were randomised. Seven patients did not receive the allocated intervention. The number of patients per group after allocation was: CI (n = 28), BCD (n = 25), CROS (n = 34), and No treatment (n = 26). In S0N0, the CI group performed significantly better when compared to baseline, and when compared to the other groups. In SpeNbe, there was an advantage for all treatment groups compared to baseline. However, in SbeNpe, BCD and CROS groups performed worse compared to baseline, whereas the CI group improved. Only in the CI group sound localisation improved and tinnitus burden decreased. In general, all treatment groups improved on disease-specific QoL compared to baseline. This RCT demonstrates that cochlear implantation for SSD leads to improved speech perception in noise, sound localisation, tinnitus burden, and QoL after 3 and 6 months of follow-up. For most outcome measures, CI outperformed BCD and CROS. Trial registration: Netherlands Trial Register (www.trialregister.nl): NTR4580, CINGLE-trial.

Cost Effectiveness of Cochlear Implantation in Single-Sided Deafness

OBJECTIVE

To analyze the cost effectiveness of cochlear implantation (CI) for the treatment of single-sided deafness (SSD).

STUDY DESIGN

Cost-utility analysis in an adapted Markov model.

SETTING

Adults with single-sided deafness in a high-income country.

INTERVENTION

Unilateral CI was compared with no intervention.

MAIN OUTCOME MEASURE

Incremental cost-effectiveness ratios were compared with different cost-effectiveness thresholds ($10,000 to $150,000) for different age, sex, and cost combinations. The calculations were based on the quality-adjusted life year (QALY), national life expectancy tables, and different cost settings. The health utility values for the QALY were either directly collected from published data, or, derived from published data using a regression model of multiple utility indices (regression estimate).

RESULTS

The regression estimate showed an increase of the health utility value from 0.62 to 0.74 for SSD patients who underwent CI. CI for SSD was cost effective for women up to 64 years ($50,000 per-QALY threshold), 80 years ($100,000 per-QALY threshold), and 86 years ($150,000 per-QALY threshold). For men, these values were 58, 77, and 84, respectively. Changing the discount rate by up to 5% further increased the cutoff ages up to 5 years. A detailed cost and age sensitivity analysis is presented and allows testing for cost effectiveness in local settings worldwide.

CONCLUSIONS

CI is a cost-effective option to treat patients with SSD.

Rerouting Hearing Aid Systems for Overcoming Simulated Unilateral Hearing in Dynamic Listening Situations

OBJECTIVES

Unilateral hearing loss increases the risk of academic and behavioral challenges for school-aged children. Previous research suggests that remote microphone (RM) systems offer the most consistent benefits for children with unilateral hearing loss in classroom environments relative to other nonsurgical interventions. However, generalizability of previous laboratory work is limited because of the specific listening situations evaluated, which often included speech and noise signals originating from the side. In addition, early studies focused on speech recognition tasks requiring limited cognitive engagement. However, those laboratory conditions do not reflect characteristics of contemporary classrooms, which are cognitively demanding and typically include multiple talkers of interest in relatively diffuse background noise. The purpose of this study was to evaluate the potential effects of rerouting amplification systems, specifically a RM system and a contralateral routing of signal (CROS) system, on speech recognition and comprehension of school-age children in a laboratory environment designed to emulate the dynamic characteristics of contemporary classrooms. It was expected that listeners would benefit from the CROS system when the head shadow limits audibility (e.g., monaural indirect listening). It was also expected that listeners would benefit from the RM system only when the RM was near the talker of interest.

DESIGN

Twenty-one children (10 to 14 years, M = 11.86) with normal hearing participated in laboratory tests of speech recognition and comprehension. Unilateral hearing loss was simulated by presenting speech-shaped masking noise to one ear via an insert earphone. Speech stimuli were presented from 1 of 4 loudspeakers located at either 0°, +45°, -90°, and -135° or 0°, -45°, +90°, and +135°. Cafeteria noise was presented from separate loudspeakers surrounding the listener. Participants repeated sentences (sentence recognition) and also answered questions after listening to an unfamiliar story (comprehension). They were tested unaided, with a RM system (microphone near the front loudspeaker), and with a CROS system (ear-level microphone on the ear with simulated hearing loss).

RESULTS

Relative to unaided listening, both rerouting systems reduced sentence recognition performance for most signals originating near the ear with normal hearing (monaural direct loudspeakers). Only the RM system improved speech recognition for midline signals, which were near the RM. Only the CROS system significantly improved speech recognition for signals originating near the ear with simulated hearing loss (monaural indirect loudspeakers). Although the benefits were generally small (approximately 6.5 percentage points), the CROS system also improved comprehension scores, which reflect overall listening across all four loudspeakers. Conversely, the RM system did not improve comprehension scores relative to unaided listening.

CONCLUSIONS

Benefits of the CROS system in this study were small, specific to situations where speech is directed toward the ear with hearing loss, and relative only to a RM system utilizing one microphone. Although future study is warranted to evaluate the generalizability of the findings, the data demonstrate both CROS and RM systems are nonsurgical interventions that have the potential to improve speech recognition and comprehension for children with limited useable unilateral hearing in dynamic, noisy classroom situations.

Systematic review of outcome domains and instruments used in designs of clinical trials for interventions that seek to restore bilateral and binaural hearing in adults with unilateral severe to profound sensorineural hearing loss ('single-sided deafness')

BACKGROUND

This systematic review aimed to identify, compare and contrast outcome domains and outcome instruments reported in studies investigating interventions that seek to restore bilateral (two-sided) and/or binaural (both ears) hearing in adults with single-sided deafness (SSD). Findings can inform the development of evidence-based guidance to facilitate design decisions for confirmatory trials.

METHODS

Records were identified by searching MEDLINE, EMBASE, PubMed, CINAHL, ClinicalTrials.gov, ISRCTN, CENTRAL, WHO ICTRP and the NIHR UK clinical trials gateway. The search included records published from 1946 to March 2020. Included studies were those as follows: (a) recruiting adults aged 18 years or older diagnosed with SSD of average threshold severity worse than 70 dB HL in the worse-hearing ear and normal (or near-normal) hearing in the better-hearing ear, (b) evaluating interventions to restore bilateral and/or binaural hearing and (c) enrolling those adults in a controlled trial, before-and-after study or cross-over study. Studies that fell just short of the participant eligibility criteria were included in a separate sensitivity analysis.

RESULTS

Ninety-six studies were included (72 full inclusion, 24 sensitivity analysis). For fully included studies, 37 exclusively evaluated interventions to re-establish bilateral hearing and 29 exclusively evaluated interventions to restore binaural hearing. Overall, 520 outcome domains were identified (350 primary and 170 secondary). Speech-related outcome domains were the most common (74% of studies), followed by spatial-related domains (60% of studies). A total of 344 unique outcome instruments were reported. Speech-related outcome domains were measured by 73 different instruments and spatial-related domains by 43 different instruments. There was considerable variability in duration of follow-up, ranging from acute (baseline) testing to 10 years after the intervention. The sensitivity analysis identified no additional outcome domains.

CONCLUSIONS

This review identified large variability in the reporting of outcome domains and instruments in studies evaluating the therapeutic benefits and harms of SSD interventions. Reports frequently omitted information on what domains the study intended to assess, and on what instruments were used to measure which domains.

TRIAL REGISTRATION

The systematic review protocol is registered on PROSPERO (International Prospective Register of Systematic Reviews): Registration Number CRD42018084274 . Registered on 13 March 2018, last revised on 7th of May 2019.

Bone-anchored hearing system, contralateral routing of signals hearing aid or cochlear implant: what is best in single-sided deafness?

PURPOSE

The aim of the study was to compare long-term results after 1 year in patients with single-sided deafness (SSD) who were fitted with different hearing aids. The participants tested contralateral routing of signals (CROS) hearing aids and bone-anchored hearing systems (BAHS). They were also informed about the possibility of a cochlear implant (CI) and chose one of the three devices. We also investigated which factors influenced the choice of device.

METHODS

Prospective study with 89 SSD participants who were divided into three groups by choosing BAHS, CROS, or CI. All participants received test batteries with both objective hearing tests (speech perception in noise and sound localisation) and subjective questionnaires.

RESULTS

16 participants opted for BAHS-, 13 for CROS- and 30 for CI-treatment. The greater the subjective impairment caused by SSD, the more likely patients were to opt for surgical treatment (BAHS or CI). The best results in terms of speech perception in noise (especially when sound reaches the deaf ear and noise the hearing ear), sound localization, and subjective results were achieved with CI.

CONCLUSION

The best results regarding the therapy of SSD are achieved with a CI, followed by BAHS. This was evident both in objective tests and in the subjective questionnaires. Nevertheless, an individual decision is required in each case as to which SSD therapy option is best for the patient. Above all, the patient's subjective impairment and expectations should be included in the decision-making process.

Hearing with One Ear: Consequences and Treatments for Profound Unilateral Hearing Loss

There is an increasing global recognition of the negative impact of hearing loss, and its association to many chronic health conditions. The deficits and disabilities associated with profound unilateral hearing loss, however, continue to be under-recognized and lack public awareness. Profound unilateral hearing loss significantly impairs spatial hearing abilities, which is reliant on the complex interaction of monaural and binaural hearing cues. Unilaterally deafened listeners lose access to critical binaural hearing cues. Consequently, this leads to a reduced ability to understand speech in competing noise and to localize sounds. The functional deficits of profound unilateral hearing loss have a substantial impact on socialization, learning and work productivity. In recognition of this, rehabilitative solutions such as the rerouting of signal and hearing implants are on the rise. This review focuses on the latest insights into the deficits of profound unilateral hearing impairment, and current treatment approaches.